/* ============================================
   Tia Shan — Author Website
   Design System & Styles
   ============================================ */

/* --- Design Tokens --- */
:root {
    /* Colors */
    --color-bg-deep: #060a14;
    --color-bg-primary: #0a0e1a;
    --color-bg-card: #0f1424;
    --color-bg-card-hover: #141a2e;
    --color-gold: #c9a961;
    --color-gold-light: #dfc48a;
    --color-gold-dim: #8a7340;
    --color-cream: #f0e6d3;
    --color-cream-muted: #b8a990;
    --color-crimson: #8b2635;
    --color-crimson-soft: #a8384a;
    --color-text-primary: #e8ddd0;
    --color-text-secondary: #9a8e80;
    --color-text-muted: #6b6158;
    --color-border: rgba(201, 169, 97, 0.15);
    --color-border-hover: rgba(201, 169, 97, 0.35);

    /* Typography */
    --font-serif: 'Cormorant Garamond', 'Georgia', serif;
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;

    /* Spacing */
    --space-xs: 0.5rem;
    --space-sm: 1rem;
    --space-md: 2rem;
    --space-lg: 4rem;
    --space-xl: 6rem;
    --space-2xl: 10rem;

    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-base: 0.4s ease;
    --transition-slow: 0.8s ease;
    --transition-glacial: 1.2s cubic-bezier(0.25, 0.1, 0.25, 1);
}

/* --- Reset & Base --- */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-sans);
    color: var(--color-text-primary);
    background-color: var(--color-bg-deep);
    line-height: 1.7;
    overflow-x: hidden;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

a {
    color: inherit;
    text-decoration: none;
}

/* --- Container --- */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-md);
}

/* --- Section Common --- */
.section {
    padding: var(--space-xl) 0;
    position: relative;
}

.section-header {
    text-align: center;
    margin-bottom: var(--space-lg);
}

.section-ornament {
    font-family: var(--font-serif);
    font-size: 0.9rem;
    color: var(--color-gold-dim);
    letter-spacing: 0.5em;
    margin-bottom: var(--space-sm);
}

.section-title {
    font-family: var(--font-serif);
    font-size: clamp(2rem, 4vw, 3rem);
    font-weight: 400;
    color: var(--color-cream);
    letter-spacing: 0.08em;
}

/* ============================================
   Navigation
   ============================================ */
.nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    padding: 1.2rem 0;
    transition: background var(--transition-base), padding var(--transition-base), backdrop-filter var(--transition-base);
}

.nav.scrolled {
    background: rgba(6, 10, 20, 0.9);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    padding: 0.8rem 0;
    border-bottom: 1px solid var(--color-border);
}

.nav-inner {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-md);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-logo {
    font-family: var(--font-serif);
    font-size: 1.5rem;
    font-weight: 500;
    color: var(--color-gold);
    letter-spacing: 0.1em;
    transition: color var(--transition-fast);
}

.nav-logo:hover {
    color: var(--color-gold-light);
}

.nav-links {
    list-style: none;
    display: flex;
    gap: var(--space-md);
}

.nav-links a {
    font-family: var(--font-sans);
    font-size: 0.85rem;
    font-weight: 400;
    letter-spacing: 0.15em;
    text-transform: uppercase;
    color: var(--color-cream-muted);
    transition: color var(--transition-fast);
    position: relative;
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 1px;
    background: var(--color-gold);
    transition: width var(--transition-base);
}

.nav-links a:hover {
    color: var(--color-gold);
}

.nav-links a:hover::after {
    width: 100%;
}

/* Mobile Toggle */
.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
}

.nav-toggle span {
    width: 22px;
    height: 1.5px;
    background: var(--color-cream-muted);
    transition: var(--transition-fast);
}

/* ============================================
   Hero Section
   ============================================ */
.hero {
    position: relative;
    height: 100vh;
    min-height: 600px;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
}

.hero-bg {
    position: absolute;
    inset: 0;
    z-index: 0;
}

.hero-bg-img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    object-position: center;
    filter: brightness(0.4) saturate(0.7);
}

.hero-overlay {
    position: absolute;
    inset: 0;
    background: 
        linear-gradient(180deg, 
            rgba(6, 10, 20, 0.6) 0%,
            rgba(6, 10, 20, 0.2) 40%,
            rgba(6, 10, 20, 0.3) 60%,
            rgba(6, 10, 20, 0.95) 100%
        ),
        radial-gradient(ellipse at center, transparent 0%, rgba(6, 10, 20, 0.4) 100%);
}

.hero-content {
    position: relative;
    z-index: 1;
    text-align: center;
    padding: var(--space-md);
}

.hero-ornament {
    font-size: 1rem;
    color: var(--color-gold-dim);
    letter-spacing: 0.5em;
    margin: var(--space-sm) 0;
    opacity: 0;
    animation: fadeIn 1.5s ease 0.3s forwards;
}

.hero-title {
    font-family: var(--font-serif);
    font-size: clamp(3rem, 8vw, 6rem);
    font-weight: 300;
    color: var(--color-cream);
    letter-spacing: 0.15em;
    line-height: 1.1;
    margin: var(--space-sm) 0;
    opacity: 0;
    animation: fadeInUp 1.5s ease 0.5s forwards;
}

.hero-subtitle {
    font-family: var(--font-serif);
    font-size: clamp(1rem, 2.2vw, 1.4rem);
    font-weight: 300;
    font-style: italic;
    color: var(--color-cream-muted);
    letter-spacing: 0.05em;
    max-width: 600px;
    margin: 0 auto;
    opacity: 0;
    animation: fadeInUp 1.5s ease 0.8s forwards;
}

.hero-cta {
    display: inline-block;
    margin-top: var(--space-md);
    padding: 0.9rem 2.5rem;
    font-family: var(--font-sans);
    font-size: 0.8rem;
    font-weight: 400;
    letter-spacing: 0.2em;
    text-transform: uppercase;
    color: var(--color-gold);
    border: 1px solid var(--color-gold-dim);
    background: transparent;
    transition: all var(--transition-base);
    opacity: 0;
    animation: fadeIn 1.5s ease 1.2s forwards;
}

.hero-cta:hover {
    background: rgba(201, 169, 97, 0.1);
    border-color: var(--color-gold);
    transform: translateY(-2px);
    box-shadow: 0 4px 30px rgba(201, 169, 97, 0.15);
}

/* Scroll Hint */
.hero-scroll-hint {
    position: absolute;
    bottom: 2rem;
    left: 50%;
    transform: translateX(-50%);
    z-index: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
    opacity: 0;
    animation: fadeIn 1.5s ease 1.5s forwards;
}

.hero-scroll-hint span {
    font-family: var(--font-sans);
    font-size: 0.65rem;
    letter-spacing: 0.3em;
    text-transform: uppercase;
    color: var(--color-text-muted);
}

.scroll-line {
    width: 1px;
    height: 40px;
    background: linear-gradient(180deg, var(--color-gold-dim), transparent);
    animation: scrollPulse 2s ease-in-out infinite;
}

/* ============================================
   Books Section
   ============================================ */
.books-section {
    padding-top: var(--space-xl);
    padding-bottom: var(--space-xl);
}

.book-card {
    display: grid;
    grid-template-columns: 300px 1fr;
    gap: var(--space-lg);
    align-items: start;
    margin-bottom: var(--space-2xl);
    position: relative;
}

.book-card:last-child {
    margin-bottom: 0;
}

.book-card-reverse {
    grid-template-columns: 1fr 300px;
}

.book-card-reverse .book-cover-wrapper {
    order: 2;
}

.book-card-reverse .book-info {
    order: 1;
}

/* Book Cover */
.book-cover-wrapper {
    position: relative;
    perspective: 1000px;
}

.book-cover {
    width: 100%;
    border-radius: 4px;
    box-shadow: 
        0 20px 60px rgba(0, 0, 0, 0.5),
        0 0 40px rgba(201, 169, 97, 0.05);
    transition: transform var(--transition-slow), box-shadow var(--transition-slow);
}

.book-cover-wrapper:hover .book-cover {
    transform: rotateY(-5deg) translateY(-8px);
    box-shadow: 
        0 30px 80px rgba(0, 0, 0, 0.6),
        0 0 60px rgba(201, 169, 97, 0.1);
}

.book-cover-glow {
    position: absolute;
    inset: -20px;
    background: radial-gradient(ellipse at center, rgba(201, 169, 97, 0.08), transparent 70%);
    pointer-events: none;
    opacity: 0;
    transition: opacity var(--transition-slow);
}

.book-cover-wrapper:hover .book-cover-glow {
    opacity: 1;
}

/* Book Info */
.book-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-bottom: var(--space-sm);
}

.book-tag {
    font-family: var(--font-sans);
    font-size: 0.65rem;
    font-weight: 500;
    letter-spacing: 0.15em;
    text-transform: uppercase;
    color: var(--color-gold);
    padding: 0.35rem 0.8rem;
    border: 1px solid rgba(201, 169, 97, 0.25);
    border-radius: 2px;
    background: rgba(201, 169, 97, 0.05);
}

.book-title {
    font-family: var(--font-serif);
    font-size: clamp(1.8rem, 3.5vw, 2.5rem);
    font-weight: 500;
    color: var(--color-cream);
    letter-spacing: 0.04em;
    line-height: 1.2;
    margin-bottom: 0.3rem;
}

.book-subtitle {
    font-family: var(--font-serif);
    font-size: 1rem;
    font-style: italic;
    color: var(--color-text-muted);
    margin-bottom: var(--space-md);
    letter-spacing: 0.03em;
}

.book-description {
    margin-bottom: var(--space-md);
}

.book-description p {
    font-family: var(--font-sans);
    font-size: 0.95rem;
    font-weight: 300;
    line-height: 1.8;
    color: var(--color-text-secondary);
    margin-bottom: var(--space-sm);
}

.book-description p:last-child {
    margin-bottom: 0;
}

.book-description strong {
    color: var(--color-cream);
    font-weight: 500;
}

.book-description em {
    color: var(--color-cream-muted);
    font-style: italic;
}

/* Buy Button */
.book-buy-btn {
    display: inline-flex;
    align-items: center;
    gap: 0.8rem;
    padding: 1rem 2rem;
    font-family: var(--font-sans);
    font-size: 0.8rem;
    font-weight: 400;
    letter-spacing: 0.15em;
    text-transform: uppercase;
    color: var(--color-bg-deep);
    background: linear-gradient(135deg, var(--color-gold), var(--color-gold-light));
    border: none;
    border-radius: 2px;
    transition: all var(--transition-base);
    position: relative;
    overflow: hidden;
}

.book-buy-btn::before {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(135deg, var(--color-gold-light), #e8d8a8);
    opacity: 0;
    transition: opacity var(--transition-base);
}

.book-buy-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 30px rgba(201, 169, 97, 0.3);
}

.book-buy-btn:hover::before {
    opacity: 1;
}

.btn-text, .btn-arrow {
    position: relative;
    z-index: 1;
}

.btn-arrow {
    transition: transform var(--transition-fast);
    font-size: 1.1rem;
}

.book-buy-btn:hover .btn-arrow {
    transform: translateX(4px);
}

/* ============================================
   About Section
   ============================================ */
.about-section {
    background: linear-gradient(180deg, var(--color-bg-deep) 0%, var(--color-bg-primary) 50%, var(--color-bg-deep) 100%);
}

.about-content {
    max-width: 720px;
    margin: 0 auto;
    text-align: center;
}

.about-text p {
    font-family: var(--font-serif);
    font-size: clamp(1.1rem, 2vw, 1.35rem);
    font-weight: 300;
    line-height: 2;
    color: var(--color-cream-muted);
    margin-bottom: var(--space-md);
    letter-spacing: 0.02em;
}

.about-text p:last-child {
    margin-bottom: 0;
    color: var(--color-text-muted);
    font-style: italic;
}

/* ============================================
   Contact Section
   ============================================ */
.contact-section {
    padding-bottom: var(--space-lg);
}

.contact-content {
    text-align: center;
    max-width: 500px;
    margin: 0 auto;
}

.contact-intro {
    font-family: var(--font-serif);
    font-size: 1.15rem;
    font-weight: 300;
    color: var(--color-cream-muted);
    line-height: 1.8;
    margin-bottom: var(--space-md);
}

.contact-email {
    display: inline-block;
    font-family: var(--font-sans);
    font-size: 1.1rem;
    font-weight: 400;
    letter-spacing: 0.05em;
    color: var(--color-gold);
    padding: 0.8rem 2rem;
    border: 1px solid var(--color-border);
    transition: all var(--transition-base);
    margin-bottom: var(--space-md);
}

.contact-email:hover {
    border-color: var(--color-gold);
    background: rgba(201, 169, 97, 0.05);
    box-shadow: 0 0 30px rgba(201, 169, 97, 0.1);
}

.contact-note {
    font-family: var(--font-serif);
    font-size: 1rem;
    font-style: italic;
    color: var(--color-text-muted);
    line-height: 1.8;
}

/* ============================================
   Footer
   ============================================ */
.footer {
    padding: var(--space-lg) 0 var(--space-md);
    border-top: 1px solid var(--color-border);
    text-align: center;
}

.footer-ornament {
    font-size: 0.8rem;
    color: var(--color-gold-dim);
    margin-bottom: var(--space-sm);
}

.footer-text {
    font-family: var(--font-sans);
    font-size: 0.75rem;
    color: var(--color-text-muted);
    letter-spacing: 0.1em;
}

/* ============================================
   Animations
   ============================================ */
@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes scrollPulse {
    0%, 100% { opacity: 0.3; transform: scaleY(1); }
    50% { opacity: 0.8; transform: scaleY(1.2); }
}

/* Scroll Reveal */
.reveal {
    opacity: 0;
    transform: translateY(40px);
    transition: opacity var(--transition-glacial), transform var(--transition-glacial);
}

.reveal.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ============================================
   Responsive Design
   ============================================ */
@media (max-width: 900px) {
    .book-card,
    .book-card-reverse {
        grid-template-columns: 1fr;
        gap: var(--space-md);
        max-width: 500px;
        margin-left: auto;
        margin-right: auto;
    }

    .book-card-reverse .book-cover-wrapper {
        order: 0;
    }

    .book-card-reverse .book-info {
        order: 0;
    }

    .book-cover-wrapper {
        max-width: 260px;
        margin: 0 auto;
    }

    .book-info {
        text-align: center;
    }

    .book-tags {
        justify-content: center;
    }

    .section {
        padding: var(--space-lg) 0;
    }
}

@media (max-width: 640px) {
    .nav-links {
        display: none;
        position: fixed;
        top: 0;
        left: 0;
        right: 0;
        bottom: 0;
        background: rgba(6, 10, 20, 0.97);
        backdrop-filter: blur(20px);
        -webkit-backdrop-filter: blur(20px);
        flex-direction: column;
        align-items: center;
        justify-content: center;
        gap: var(--space-lg);
    }

    .nav-links.open {
        display: flex;
    }

    .nav-links a {
        font-size: 1.2rem;
        letter-spacing: 0.2em;
    }

    .nav-toggle {
        display: flex;
        z-index: 1001;
    }

    .nav-toggle.active span:nth-child(1) {
        transform: rotate(45deg) translate(4px, 4px);
    }

    .nav-toggle.active span:nth-child(2) {
        opacity: 0;
    }

    .nav-toggle.active span:nth-child(3) {
        transform: rotate(-45deg) translate(5px, -5px);
    }

    .hero-title {
        font-size: clamp(2.5rem, 12vw, 4rem);
    }

    .book-cover-wrapper {
        max-width: 220px;
    }

    .container {
        padding: 0 1.2rem;
    }
}

/* ============================================
   Ambient Particles (canvas layer)
   ============================================ */
#particles-canvas {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 0;
    opacity: 0.4;
}

/* Ensure content is above particles */
.nav, .hero, .section, .footer {
    position: relative;
    z-index: 1;
}